Nasopharyngeal carcinoma (NPC) is the most prevalent ENTtumour in Indonesia. We investigated the primary diagnostic value of Epstein-Barr virus (EBV) DNA load and mRNA detection in noninvasive nasopharyngeal (NP) brushings, obtained prospectively from consecutive Indonesian ENT-patients with suspected NPC (N 5 106) and controls. A subsequent routine NP biopsy was taken for pathological examination and EBER-RISH, yielding 85 confirmed NPC and 21 non-NPC tumour patients. EBV DNA and human DNA load were quantified by real-time PCR. NP brushings from NPC patients contained extremely high EBV DNA loads compared to the 88 non-NPC controls (p < 0.0001). Using mean EBV DNA load in controls plus 3 SD as cut-off value, specificity, sensitivity, positive and negative predictive values were 98, 90, 97 and 91%, respectively. Epstein-Barr nuclear antigen 1 (EBNA1) and the carcinoma-specific BARF1 mRNA were detected by nucleic acid sequence based amplification and found in 86 and 74% of NP brushings, confirming NPC tumour cell presence. EBV RNA positivity was even higher in fresh samples stored at 280°C until RNA expression analyses (88% for both EBNA1 and BARF1). EBV RNA-negative NP brushings from proven NPC cases had the lowest EBV DNA loads, indicating erroneous sampling. No EBV mRNA was detected in NP brushings from healthy donors and non-NPC patients. In conclusion, EBV DNA load measurement combined with detection of BARF1 mRNA in simple NP brushings allows noninvasive NPC diagnosis. It reflects carcinoma-specific EBV involvement at the anatomical site of tumour development and reduces the need for invasive biopsies. This procedure may be useful for confirmatory diagnosis in large serological NPC screening programs and has potential as prognostic tool. ' 2006 Wiley-Liss, Inc.Key words: EBV; NPC; diagnosis; viral load; oncogene; carcinoma Undifferentiated nasopharyngeal carcinoma (NPC WHO type III) is virtually 100% associated with Epstein-Barr virus (EBV) and has a reported high incidence in most of South-East Asia and intermediate incidence in North-African populations and in Inuit. [1][2][3] In Indonesia, with an ethnically diverse population of 225 million people, NPC is the most common ENT tumour with high prevalence among native populations and a yearly overall incidence estimated at 6.2/100,000. 4 Extremely high incidence was recently documented in native populations living on the island of Sulawesi. 5 In Yogyakarta, Central Java, NPC is the most prevalent tumour among man and 4th most prevalent among females, with a male/female ratio of 2.4, constituting respectively 22 and 8% of all diagnosed malignancies. 4 The strong etiological link between EBV and NPC has been known for over 3 decades [1][2][3]6 and is reflected by abnormal anti-EBV antibody profiles, increased circulating EBV DNA levels and by distinct EBV gene expression in the tumour cells. 7-11 Classically, NPC is considered to have a latency type 2 EBV transcription, with expression of EBV-encoded small RNAs 1 and 2 (EBER1/2), BamHI A rightward transcript...
Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in Southeast Asia and is strongly associated with Epstein-Barr virus (EBV).We investigated the primary diagnostic value of circulating EBV DNA and anti-EBV immunoglobulin G (IgG) and IgA levels in Indonesian NPC patients (n ؍ 149). By a 213-bp Epstein-Barr virus nuclear antigen 1 (EBNA1)-based real-time LightCycler PCR, 72.5% of patients were positive for EBV DNA in whole blood, with 29.5% having levels above a previously determined clinical cutoff value (COV) of 2,000 EBV DNA copies/ml, the upper level in healthy carriers. In a 99-bp LightCycler PCR, 85.9% of patients were positive and 60.4% had levels above the COV. This assay quantified a significantly higher EBV load than the 213-bp PCR assay (P < 0.0001), suggesting that circulating EBV DNA is fragmented. Using data from 11 different studies, we showed a significant inverse correlation between PCR amplicon size and the percentage of patients positive for circulating EBV DNA (Spearman's rho ؍ ؊0.91; P < 0.0001). EBV DNA loads were unrelated to anti-EBV IgG or IgA levels, as measured by VCA-p18 and EBNA1-specific synthetic peptide-based enzyme-linked immunosorbent assays. The presence of circulating tumor cells was assessed by amplification of BamHI-A rightward frame 1 (BARF1) mRNA, a viral oncogene abundantly expressed in EBV-carrying carcinomas but virtually absent from EBV-associated lymphomas. Despite high EBV DNA loads and the presence of EBNA1 and human U1A small nuclear ribonucleoprotein mRNA, BARF1 mRNA was never detected in blood. We conclude that amplicon size significantly influences EBV DNA load measurement in NPC patients. The circulating EBV DNA load is independent of serological parameters and does not reflect intact tumor cells. The primary diagnostic value of the EBV DNA load for the detection of NPC is limited.
Small B-cell non-Hodgkin lymphoma (NHL) is difficult to be distinguished from non-neoplastic reactive process using conventional haematoxylin and eosin (H&E) staining due to different interpretation among pathologists to diagnose based on morphologic features. Ancillary examination such as immunohistochemical (IHC) staining is essential to be conducted. However, a negative or doubtful result is sometimes obtained due to unsatisfying tissue processing or IHC technique. Polymerase chain reaction (PCR) as a molecular diagnostic technique is very sensitive and specific. Clonality detection of heavy chain immunoglobulin (IgH) gene rearrangement has been widely used to establish diagnosis of B-cell NHL. Aims: To elaborate interobserver variation in small B-cell NHL diagnosis based on morphologic features only and to confirm sensitivity and specificity of PCR technique as an ancillary method. Methods: The 28 samples of small B cell NHL and suspicious lymphoma were interpreted by 3 pathologists in Sardjito General Hospital based on their morphology only. The reliability of assessment and the coefficient of interobserver agreement were calculated by Fleiss kappa statistic. Interpretation results were confirmed with IHC staining (CD20, CD3, Bcl2). PCR was performed to analyze the clonality of IgH gene rearrangement. Results: Interobserver agreement in morphologic evalution of small B cell NHL and chronic lymphadenitis revealed kappa coefficient 0.69 included in substantial agreement category. The cases were divided into 3 groups based on morphology and IHC result; lymphoma, reactive process; and undetermined group. PCR analysis showed 90% sensitivity and 60% specificity. Conclusions: The present study reveals a substantial agreement among pathologists on small B-cell NHL diagnosis. On difficult cases, PCR is useful as a complementary method for morphologic and IHC examinations to establish definitive diagnosis.
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